Waterproof-type control units are widely used that comprise: a casing made up of a base and a cover; a circuit board that is hermetically accommodated in the casing; a circuit component and a plurality of contact terminals for external connection, mounted on the circuit board; and a connector housing having a partition wall into which the contact terminals are press-fitted; wherein in order to expose the end face of the connector housing out of the casing there is provided a waterproof sealing material that fills a first sealing gap provided at an abutment surface of the connector housing and the cover, a second sealing gap provided at an abutment surface of the connector housing and the base, and a third sealing gap provided at an abutment surface of the base and the cover.
In the sealing structure for an electronic control device in Japanese Patent Application Publication No. 2013-069735 (FIG. 1 and FIG. 8), for instance, a casing seal portion 50A is provided on a joining surface of peripheral edges of a cover 13 and a case (corresponding to the base of the present application) 12 that clamp a connector (corresponding to the connector housing of the present application) 15; a connector seal portion 50B is provided at a joining surface of the outer peripheral surface of the connector 15 and the inner peripheral face of the casing; a seal groove 51 is provided on one of the seal portions 50A, 50B, and a ridge is provided on the other; a gap having a U-shaped cross-section, between the seal groove 51 and the ridge, is filled with a sealant (corresponding to the waterproof sealing material of the present application); and an auxiliary seal groove 58 and an auxiliary ridge 59 that fit into each other are provided, across a predetermined gap, at the opposing surfaces of the seal groove 51 and the ridge, at a joint portion at which the two seal portions 50A, 50B intersect at a predetermined angle. As a result, a sealing structure is provided in which there is suppressed loss of sealability at the joint portion between the casing seal portion and the connector seal portion.
In the waterproof-type electronic apparatus and assembly method thereof of Japanese Patent Application Publication No. 2012-069611 (paragraph [0047], FIG. 7 and FIG. 12), an end section of a recessed stripe on a base 200 side and an end section of a recessed stripe on a cover 400 side are formed in wide recesses 230d1, 230d2 and 420c1, 420c2, at intersections C1, C2. These wide recesses are utilized as fused portions of the sealing material 500 with which a first seal portion and a second seal portion is coated; thereby, a gapless sealing process can be carried out in which a fusion surface area is expanded while causing excess sealing material that arises at a fusion point of a non-annular sealing material and an annular sealing material to be engulfed into the opposing wide recess.
Further, Japanese Patent Application Publication No. 2012-069611 discloses (FIG. 17, FIG. 18, paragraph [0004]) a first assembly method and a second assembly method as methods for assembling a waterproof-type electronic apparatus, wherein the first assembly method involves coating firstly a second sealing gap surface of a base with a waterproof sealing material; arranging next, on the base, a circuit board having a connector housing mounted thereon; coating next a first sealing gap of the connector housing and a third sealing gap of the base with waterproof sealing material, in a ring-like fashion; and attaching and fastening next the cover. The second assembly method involves coating firstly a first sealing gap surface of a base with a waterproof sealing material; arranging next, on the cover, a circuit board having a connector housing mounted thereon; coating next a second sealing gap of the connector housing and the third sealing gap of the base with waterproof sealing material, in a ring-like fashion; and attaching and fastening next the base.